Cardiac rhythm management devices are implantable cardiac devices that provide electrical stimulation to selected chambers of the heart in order to treat disorders of cardiac rhythm. Examples of such devices include pacemakers and implantable cardioverter/defibrillators (ICDs). Cardiac devices rely upon their sensing capability in order to appropriately deliver stimulation to the heart. For example, pacemakers usually are programmed to deliver bradycardia pacing in a synchronous mode where paces are inhibited or triggered by sensed intrinsic cardiac activity. ICDs deliver shock therapy to the heart when the sensed cardiac activity indicates the presence of a tachyarrhythmia.
MRI (magnetic resonance imaging) scans pose risks to pacemaker and ICD patients due to possibility of interference with cardiac sensing which could cause inappropriate delivery of electrical stimulation. In order to mitigate these risks, devices are often reprogrammed to a non-sensing operating mode for the duration of the scan. However, device re-programming requires the intervention of both a knowledgeable professional and specialized equipment, neither of which may be conveniently available.